Bag and method of forming the same



April 4, 1933. T. E. coTY I BAG AND METHOD OF FORMING THE SAME- FiledAug. 5, 1930 awmgzszvrok.

BY 6 t :TToRNEYs.

Patented Apr. 4, 1933 PATENT; OFFICE THOMAS EARL COTY, OF WATERTOWN',NEW YORK IBA'G AND METHOD or FORMING THE SAME Application filed August5, 1930. Serial No. 473,236.

My present invention relates to the concrossing the end of the uppersheet of the web struction of bags, particularly of paper bags, and isdescribed with that fact in mind, although I do not intend to excludewebs formed 5 of other materials from the scope of the claims.

.One of the principal difficulties with the present form of closedbottom bag is that fine materials, flour, carbon black, cement, etc.,tend to sift out of the bottom of the bag at the seams. This is due inlarge part to the fact that in ordinary constructions of bag it is notpossible to apply paste to the inner side of the folds, where the sidefolds are folded upon themselves, for reasons which will be apparent asthis specification is continued. The slits which are cut in both webs inorder to permit the opening of the bag and the turning in of the sidefolds, are cut usu- 0 ally parallel to the sides of the bag, and as willbe observed, when the side folds of the bag are turned over in thefolding, their rear faces have no paste applied thereto and tend to forma valve with the webs, into which the soft material penetrates and bywedging action, extends the gap and opens the pasted seam until itssplits to a greater or less extent. It is the object of the presentinvention to provide a substantially sift-proof bag. 0 WVhen the new bagis properly formed with suflicient overlap in the seams and a goodquality of paste, its efficiency is almost, if not quite, one hundredpercent, and even at the 5 high speed of operation of the modern bagmachines, and the imperfections which inevitably arise in allmanufacturing processes, its efficiency is very high and very muchgreater than that of any other bag with which I am familiar. In oneaspect, the improvement consists in cutting away the slits on the sidesadjacent to the sides of the bag so that they are formed polygonally; inthe present embodiment of the invention, the triangular form is used.The effect of this is that when the end of the bag is opened up in orderto apply the paste, the parts which act as a valve in the ordinary bagto which I have referred are cut off, and it is possible to apply thepaste so that the side folds are securely fastened in place, the side ofthe polygon diagonally, and the fold being pasted both to the upper weband to the lower one at that point, making a secure seal with no loosepart generating any wedging action to open it.

I believe this method of forming bags to be broadly new, and have testedit severely without failure.

The accompanying drawing shows embodiments of my invention. ThereinFigure 1 shows the end of a blank after cutting the slits; Figure 2shows the bottom partly opened; Figure 3 shows the blank after the endis opened and the paste applied; Figure 4 when the flaps are turned upby the creasers; Figure 5 shows the end of the bag after the folds arepressed in place; and Figure 6 shows a common form of bag-end in processof manufacture, with the defect referred to somewhat exaggerated to makeit clearly {9 apparent.

I will describe Figure 6 first, in order to point out this defect. A isthe back-flap formed on the upper sheet of the tube; 13 is the thumb-tabformed on the lower sheet. At a, a are shown the corners of theside-folds, which open slightly when pulverulent material sifts in andby the wedging action of its weight forces open one or more seams andsifts out.

The method of preventing this is shown in Figures 1 to 5. Theconstruction illustrated is so simple as to be self-explanatory. A isthe upper sheet of the blank as it comes from the tuber; A A are theparts of sheet A used in the side folds; B B are the corresponding partsof the lower sheet; (1, C are polygonal notches, in this casetriangular, which pass through both sheets, taking the place of theusual slits; one side of each notch is preferably parallel with the edgeof the blank, and the hypotenuse of the triangle is substantially normalto the line between the upper angle of the notch and the side of theblank at the crease, as shown in Figure l; but other polygons might beused, provided the line crosses the creases joining the upper and lowersheets of the web to the side-folds at such an angle as to close the bagsecurely, as presently explained.

Referring now particularly to Figures 3 and 4, it will be seen that thepaste-pad is so shaped that instead of the ordinary U-shaped applicationshown in Figure 6, I apply paste also to the flap A at the parts E wherethe corners a, a of Figure 6 have been cut away to expose the flap. Atthe corners of the side-folds A B also; extending out to the diagonaledges of the flaps, as indicated at- F, F, paste is applied, as well asat the usual places, E. Perforations D, B, see Figures 1 and 2, permitpaste to pass to the under side of the web.

By this method of construction it will be seen that the wedging actionof the contents upon the corners of the closure is entirely avoided; thecorners themselves being cut away, they cannot curl up to form a pocket;and the mouth of the sac formed by the corners of the fold at F, F, isso securely sealed by my method that no sifting occurs. The limit ofendurance of these bags is not the strain of the contents upon theseams, but the strength of the material.

VVha-t is claimed as new is:

1. As a new article of manufacture, a bag formed from a tube in whichthe cuts made by the slitters of the ba -machine are polygonal, so thatthe corners of the side flaps are cut off, the lines of the cutscrossing the creaser lines of the bag-bottom at an angle other than aright angle, the paste extending substantially to the outer edges of theside flaps on the portions thereof which are folded upon themselves,sealing the corners of the bag-bottom.

2. A bag tube having both the plys at that end from which the bag bottomis to be formed provided with a pair of spaced apart incisions formingbetween them cooperating bottom flaps, the outer edge of each incisionbeing inclined outwardly so that when the opposite creased portions ofthe tube end are folded toward each other in the formation of the bagbottom the said inclined edges will extend diagonally across the line offold of the flaps for the purpose specified.

3. A bag formed from a flat tube having both of its plys at that endfrom which the bag bottom is to be formed provided with a pair of spacedapart incisions forming between them cooperating bottom fiaps, zones ofadhesive extending transversely across the outer face of each flap, theouter edge of each incision being inclined outwardly so that when theopposite creased portions of the tube end are folded toward each otherin the formation of the bag bottom the said inclined edges at each sideof the bottom will extend diagonally across the said zones of adhesiveand at an angle to the lines of fold of the flaps for the purposespecified.

4. A ba tube having the plys at one end from whic the bag bottom is tobe formed provided with a pair of spaced apart substantially V-shapednotches forming between them cooperating bottom flaps, one edge of eachnotch being inclined outwardly so that when the opposite creasedportions of the tube end are folded toward each other in the formationof the bag bottom, the said inclined edges will extend diagonally acrossthe line of fold of the flaps to provide a sift-proof seal between thecooperating flaps at the bottom of the bag.

5. A bag formed from a fiat tube having both of its plys at that endfrom which the bag bottom is to be formed provided with a pair of spacedapart substantially V-shaped notches forming between them cooperatingbottom flaps, lines of adhesive on the outer face of each flap andextending onto the two opposed companion flaps, one edge of each of saidnotches being inclined outwardly so that when the opposite creasedportions of the tube end are folded toward eachother in the formation ofthe bag bottom, the said inclined edges at each side of the bottom willextend dia onally across the said lines of adhesive and at an angle tothe lines of fold of the flaps, for the purpose specified.

Signed at Watertown, in the county of Jefferson and State of New York,this 31st day of July, A. D. 1930.

THOMAS EARL COTY.

